Actions for selected content:

Send content to

To send content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about sending content to .

To send content items to your Kindle, first ensure no-reply@cambridge.org
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about sending to your Kindle.

Note you can select to send to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.

By using this service, you agree that you will only keep articles for personal use, and will not openly distribute them via Dropbox, Google Drive or other file sharing services
Please confirm that you accept the terms of use.

We have prepared in situ REBa2Cu3O7 (REBCO) (RE= Y, Pr, Dy) thin films and YBC0/Dy(Pr)BC0 superlattices by single target dc planar magnetron sputtering. YBCO/DyBCO superlattices have been realized with modulation wavelength as short as 24Å, i.e., a unit cell of YBCO alternates with a unit cell of DyBCO, on average. The superconducting properties of such superlattices are indistinguishable from those of single layers. Tco's (zero resistance) are between 85 and 89K, and the residual resistivity ratios are between 2.5 and 3. In contrast to these results, when YBCO is layered with PrBCO, which is insulating, a dramatic change in the superconducting properties is observed. We have been able to artificially vary the coupling between single 12Å unit cell of YBCO by interposing insulating planes of PrBCO. As the YBCO layer separation increases, T is reduced and the transition broadens showing evidence of 2‐D superconducting fluctuations.

We report on the growth and properties of (Sr1-xCax)Ru03 and Sr(Ru1-xTix)O3 thin films obtained by pulsed laser deposition. A sequential deposition of sub-monolayers from SrTiO3 and CaRuO3 end members has been successfully used to substitute Ca- and Ti- in the SrRuO3 perovskite structure. Magnetization measurements as well as transport properties exhibit very different behavior for each type of substitution. In the case of Ca- substituted samples, the resistivity remains metallic and is consistent with the expected behavior for intermediate compositions. A progressive reduction of the Curie temperature with higher doping is reported. In the case of Ti- substituted samples, we observe a stronger reduction of the Curie temperature and remanent magnetization with increasing Ti substitution. Resistivity as a function of temperature shows a crossover from metallic to semiconducting behavior with variable range hopping process for a high level of Ti doping and points out the clear differences between the two substitutions sites. In both cases, the observed reduction of the magnetization with increasing doping concentration can be well described by assuming a random distribution of substituted sites in the perovskite structure.

We report on ferroelectric field effect experiments in ultrathin layers of the metallic perovskite SrRuC<3 using Pb(Zr0.52Ti0.48)O3/SrRuO3 epitaxial heterostructures. Switching the ferroelectric polarization of the Pb(Zr0.52Ti0.48)O3 layer induces a ∼ 10% change in the sheet resistance of the SrRuO3 layer that is nonvolatile and also reversible. Hall effect measurements that take into account the anomalous Hall effect reveal a carrier concentration of n ∼ 2 × 1022 electrons/cm3 and allow us to understand quantitatively the sign and magnitude of the observed resistance change. Of key importance for these experiments is the crystalline and surface quality of the SrRuO3 and Pb(Zr0.52Ti0.48)O3 layers. We also discuss how this general approach of nonvolatile doping using ferroelectrics opens new possibilities of directly creating small electronic structures without using traditional lithographic techniques.

The relationship between the magnetic and crystalline microstructure of SrRu03 thin films is analyzed using transmission electron microscopy. Regions with a stripe magnetic domain structure in different orientations are observed in Lorentz imaging mode when the specimens are zero-field-cooled through the ferromagnetic transition temperature, Tc ≈ 150K. The different orientations of the stripe regions correspond to different crystallographic domains as determined by electron diffraction and magnetic image contrast; all of the six possible orientations of the orthorhombic SrRuO3 structure grown epitaxially on a SrTiO3 cubic substrate are identified. The results show that the uniaxial anisotropy indicated for these multi(crystal)domain films is the same as that determined for single crystal films by bulk magnetization measurements, and is therefore primarily magnetocrystalline in nature.

Using scanning probe microscopy, we have written nonvolatile electronic nanofeatures in the metallic perovskite oxide SrRuO3. The structures were written in epitaxial thin film Pb(Zr0.52Ti0.48)O3 (PZT) / SrRuO3 heterostructures by locally switching the polarization field of the ferroelectric PZT layer with an atomic force microscope (AFM). The resulting field effect changes the sheet resistance of the SrRuO3 layer by up to 300 ohms per square. Using the AFM as an electric field microscope, it is also possible to visualize the charge distribution of the written areas on the PZT surface. Large areas of up to 100 μm2 have been polarized and imaged with submicrometer resolution, with the smallest features having linewidths of 170 nm. This approach to local electronic doping is reversible and allows one to write nonvolatile submicron electronic features in two dimensions without lithographic steps or permanent electrical contacts required.

Recommend this

Email your librarian or administrator to recommend adding this to your organisation's collection.